Railway trains and cars typically include a pneumatic brake system. The brake system is critical to the safe operation of the rail cars and is therefore subject to periodic testing to ensure the integrity and satisfactory performance of the brake system. The present invention provides a test device and method for testing the brake system on a rail car.
In the United States, the Association of American Railroads (AAR), in conjunction with the Federal Railway Administration, has promulgated and adopted a Manual of Standards and Recommended Practices. Included in this manual is Standard S-486 for testing the brake system on a rail car. In general, Standard S-486 includes a series of tests that measure the pressure and flow rate of the air in the brake system under various conditions. These pressure and flow rate measurements are then used to verify that the brake system has sufficient physical integrity and will perform satisfactorily under expected operational conditions.
Various devices and methods exist to test rail car brake systems. For example, Standard S-486, incorporated herein by reference in its entirety for all purposes, describes and illustrates a brake system test device commonly known to one of ordinary skill in the art.
The test device described and illustrated in Standard S-486 includes a valve manifold to connect a supply of test air to the brake system being tested. The valve manifold generally includes a dual-pressure reducing valve, a six position rotary valve, and a ⅜ inch vent valve connected in series between the air supply and the brake system being tested. The dual-pressure reducing valve has two selectable positions to reduce the air supply to either 80 psig or 90 psig. The six position rotary valve selectively supplies or vents test air to or from the brake system through various sized orifices. The vent valve provides a ⅜ inch orifice for rapidly venting test air from the brake system. In addition, the test device further includes a pressure gauge and venturi flow meter for measuring the test air.
An operator using the test device described and illustrated in Standard S-486 must manually position each of the selectable valves to the proper position and in the exact sequence recited in the various tests to correctly perform each brake test. In addition, the operator must also accurately observe, interpret, and record the various pressure and flow rate measurements at the proper times to perform a valid test of the brake system. As a result, various errors can occur in the brake system test due to operator error.
Another device presently available for performing the brake tests recited in Standard S-486 is described in U.S. Pat. No. 5,808,909 issued to Rees. The test device described in this patent includes a valve manifold and pressure and flow rate sensors for performing the functions and measurements required by Standard S-486. This test device further includes a controller programmed to operate the valve manifold as prescribed by Standard S-486 and to record measurements from the pressure and flow rate sensors, thus potentially eliminating sources of operator error. According to the patent, the controller can be reprogrammed to perform different brake tests. However, the reprogramming requires individual action for each test device. This individual action causes delays in subsequent brake tests, requires additional skilled labor sufficiently knowledgeable to perform the reprogramming, and create an additional opportunity for operator error in effecting any programming changes.
As a result, the need exists for an improved test device that can not only accurately perform the brake system tests required in the industry, but that can also be reliably and rapidly updated to adapt to changing demands in the industry.